Rotary engine.



T. J. LOFTUS. ROTARY ENGINE. APPLICATION FILED OCT. 1 6. 1917.

Patented Aug. 20, 1918.

2 SHEETS-SHEETI WITNESS:

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T. 1. LOFTUS.

ROTARY ENGlNE.

APPLICATION FILED OCT. l6. 19]?- 1,276,381 Patented Aug. 20, 1918. I

I 2 SHEETSSHEET 2.

any VENTOR,

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WITNESS:

E STATES PATEN THOMAS J. LOFTUS, OF CASTELLA, CALIFORNIA, ASSIGNOR OFONE-HALF TO HARD/[ON BELL, OF OAKLAND, CALIFORNIA.

ROTARY ENGINE.

Specification of Letters latent. Patented Aug. 20, 1918.

Application filed October 16, 1917. Serial No. 196,819.

To all whom it may concern:

Be it known that I, THOMAS J. Lor'rus, a citizen of the United States,residing at Castella, in the county of Shasta and State of California,have invented new and useful Improvements in Rotary Engines, of whichthe following is a specification.

This invention relates to a rotary engine of the internal combustion,multi cylinder t pe, and particularly to improvements over t e structureshown in my co-pending application entitled rotary engine, filed August15th, 1917, Serial Number 186,306.

One of the objects of the present inven-.

tion is to provide a rotary cylinder, internal combustion engineoperating on the fourcycle principle, in which the crank case andcylinder are mounted eccentrically with relation to the crank shaft andin which both the cylinders and crank shaft revolve. An-- other objectof the invention is to provide a crank shaft to which two revolutionsare imparted while the cylinders make one revolution; and also toprovide a novel cam arrangement whereby two reciprocations are impartedto the pistons during one revolution of the cylinders to permit aperfect charging and scavenging of the cylinders. Further objects willhereinafter appear.

The invention consists of the parts and the construction and combinationof parts as hereinafter more fully describedv and claimed, havingreference to the accompanying drawings, in Which Figure 1 is a central.vertical, longitudinal section through the engine.

Fig. 2 is a central, vertical, cross section.

Fig. 3 is a'front view of the cam head, showing the position of theinlet valve cam.

Fig. 4 is a front view of the cam head which carries the exhaust valvecam.

Fig. 5 is another view of one of the cam heads. showing a modificationin the construction of same.

Referring to the drawings in detail, A and B indicate a pair of bearingmembers, in

which are journaled, respectively, a crank shaft 2 and a cylinder shaft3. Suitably secured or formed integral with the cylinder shaft is acrank casing 4, and radially positioned with relation to the cylindershaft exlliaust valve 7 and aninlet valve 8, the va ves employed beingof the puppet type.

Each valve is provided with a stem 9 surrounded by a spring 10 whichengages a collar 11, thereby providin a means for normally retainingeach Va ve on its seat.

bearing B. The cylinder" shaft is journaled both in the bearing B and onthe stationary shaft 16. The cylinder shaft may, therefore, be termed asleeve shaft having both an interior and an exterior support. One sideof the crank case supporting the cylinders is provided with a number ofcored passages 17, one for each cylinder and inlet valve 8.

The inner ends of these cored passages communicate with perforations'formedin the sleeve shaft and also in the hollow stationary shaft 16,while the outer ends are connected through pipes 18 with the intakeports formed in the cylinders. .The hollow stationary shaft may,therefore, be directly connected with a carbureter of any suitableconstruction and the gas admitted will thus' travel through thestationary, hollow shaft and the perforations formed therein, thencethrough the cored passages and pipes 18 directly to each inlet valve,the admission of gas being controlled by opening and closing the inletvalves by means of a cam 19 formed on the outer head l-l; that is, theinner ends ofthe stems carrying the valves 8 are so positioned that theywlll engage the cam 19 once during each revolution of the cylinders,thus providing a means for lifting each inlet valve once during eachrevolution of the cylinders. The exhaust valves are also opened onceduring each revolution of the cylinders by means of a cam 20 formed onthe outer periphery of the stationary cam head 13.

I'journal section 23. These journal sections periphery of the stationarycam are separated, as shown at 2 1, to permit the connecting arms tostraddle the crank arms 25 carried by the crank shaft and also to permita perfect engagement, as will hereinafter be described, with adoublecrank pin 26 carried by each crank. One side of each journalmember 23 is provided with a pin extension 27 which supports a roller28, said rollers being so positioned that they will always .run inengagement with a pair of circular cam grooves 29 and 30 formed in eachca'm head 13 and 1 1.

The crank shaft, as previously stated, is

eccentrically positioned with relation to the.

crank case and the cylinders. The crank arms and pins 26 carried therebyare, furthermore, so short that a positive connection between the rigidpiston connecting rods and the pins cannot be obtained. It may,furthermore, be stated that such engagement 'is neither desired norintended, as one of the objects of the present inventionis to permit tworeciprocations of each piston and two complete revolutions of the crankshaft to each revolution of the cylinders, the two reciprocations of thepistons during one'revolution of the cylinders permitting a four-cycleoperation and simultaneously reduces the cylinder speed to onehalf ofthat which-is required in ordinary standard four-cycle revolvingcylinder engines. The centrifugal strains to which such cylinders aresubjected are entirely overcome by the present structure, as thecomparatively slow speed of the cylinders with relation to the crankshaft permits a high propeller speed and a low cylinder speed. Lightermaterial and a more compact construction and assembly are also permittedin the present instance; and the emciency is rather higher, due to thelonger opening period of both the intake and exhaust valves.

The operation of the engine will be as follows: Referring to Figs. 2, 3and 4, the sweep of the crank pins 26 conforms to or travels in exactalinement with the lower half 30 of the cam grooves formed in the heads13 and 14. The movement of the pistons is not only positively timedand'regulated by the grooves 29 and 30 but also by the revolution of thecrank shaft. To illustrate the movement of the pistons during onerevolution, we might commence with the suction stroke of a singlepiston. In that instance, commencing with the piston shown in cylinder5*, which is in alinement with the intake cam 19, it might be statedthat the inlet valve remains open during the travel of the cylinder fromthe point indicated at 31 to the point 32. The piston travels inwardlyduring this movement of the cylinder, due to the engagement of therollers 28 with the upper half of the cam groove 29, a complete inwardmovement of navaser the piston being obtained when the cylinder reachesthe point 32. The piston will similarly travel outward until the point33 is reached, thus fully compressing the charge admitted. This outwardmovement is due not only to the shape of the lower half ofthe camgrooves 30, but also to the fact that the connecting rod bearings 23 areengaged by the crank pins'26, thereby forcing the piston outwardlyduring the revolution of the cylinders from the point 32- to the point33.

Ignition takes place in a position preferably ahead of the point 33- andburning of the gases will, therefore, force the piston inwardly againstthe crank pins, thereby imparting the power stroke; a complete expansionor burning of the gases having taken place when the cylinder reaches thepoint 34. The exhaust cam, carried by the head 13, is engaged at thispoint and the valve remains open while the cylinder travels from theposition shown at 31 to the point 31 and outward movement of the pistonbeing insured by the shape of the upper half of the cam grooves 29.

One reciprocation of each piston takes place while the pistons travel inengagement with their crank shaft pins and the second reciprocation ofeach piston takes place during the other half of the revolution of thecylinders or when the pistons travel free of the crank pins but inengagement with the upper halves 29 of the cam groovesl Engagement of apiston with a crank shaft pin takes place during one whole revolution ofthe crank shaft and during one half of a revolution of the cylinders,that is, a crank pin engages a piston connecting rod at the point 32,shown in Figs. 2 and 3, and does not leave the connecting rod untilthepoint 3'4 is reached. Two revolutions are transmitted to the crankshaft during one revolution of the cylinders and two reciprocations arealso transmitted to each piston during one revolution of the cylinders,thereby permitting a four-cycle operation and a complete charging andscavenging of each cylinder due to the long'opening period permitted bythe position of the cams 19 and 20.

While any suitable form of ignition system may be employed, anadjustable wlpe contact member 36 carried by the bearing I a pipe 40,the running fit preventing any unnecessary leakage around the stationarycam heads and the revolving cylinders. I also wish it understood thatthe materials and finish employed in general may be such as theexperience and judgment of the manufacturer may dictate.

The construction of the crank shaft and pistons here provided isidentical to that shown in my co-pending application, but the featurewhich forms the important part of the present application is theprovision of double cam grooves 29 and 30 and mechanically operatedvalves for the admission and scavenging of the charges, the specificconstruction and manner of introducing the charges being immaterial asit is obvious that any suitable arrangement may be provided.

By referring to Fig. 5, it will be seen that the upper cam section 29 islarger than those illustrated in Figs. 3 and 4. This is of greatimportance particularly Where an engine of the type described isemployed for aviation purposes. That is, the large cam 29 providedincreases the stroke of the piston during the scavenging and suctioncharge. Increased stroke causes the piston to enter What is normallytermed the compression space, thereby serving as a means for completelyscavenging the gases on the exhaust stroke and also serving as a meansfor increasing the volumetric charge of the cylinder during the suctionstroke. The importance of this can readily be appreciated when it istaken into consideration that aviation engines often travel at suchheights that the atmospheric pressure is so reduced that comparativelylow compression is obtained during the compression strokes of thepistons. Any increase in volumetric capacity under such conditions istherefore a vital factor in the successful operation of an engine ofthis type.

Another. feature obtained is an increase in length of both the exhaustand inlet cams which further facilitates a more complete' scav nging andcharging of the cylinders.

Having thus described my invention, what I claim and desire to secure byLetters Patent is- 1. A four-cycle rotary internal combustion enginecomprising a plurality of revolving cylinders, a revolving crank shafteccentrically positioned with relation to the cylinders, a piston ineach cylinder, means for transmitting piston movement to revolve thecrank shaft and means for transmitting two reciprocations to each pistonduring one revolution of the cylinders. said means also adapted toincrease the length of the piston stroke during one-half revolution ofthe cylinders and decrease the length during the ther half of therevolution of the cylinders.

A four-cycle rotary internal combustion engine comprising a plurality ofrevolving cylmders, a piston in each cylinder,

a rigid connecting rod in each piston, a.

ton during one revolution of the cylinders.

3. A four-cycle rotary internal combustion engine comprising a pluralityof revolving cylinders, a piston in each cylinder, a rigid connectingrod in each piston, a bearing member on the lower end of each connectingrod,.a revolving crank shaft eccentrically positioned with relation tothe cylinders, crank pins on said shaft, means causing the rigidconnecting rod bearings to engage the crank pins during one-halfrevolution of the cylinders and to transmit two revolutions to the crankshaft during one revolution of the cylinders and a pair of,

stationary cam members controlling the re oiprocal movement of eachpiston, said cam members adapted to lengthen the piston stroke duringthe exhaust and charging cycle and to decrease the stroke during thecompressing and firing cycle.

4:. A four-cycle rotary internal conibustion engine comprising aplurality of revolving cylinders, a piston in each cylinder, a rigidconnecting rod in each piston, a bearing member on the lower end of eachconnecting rod, a revolving crank shaft eccentrically positioned withrelation to the cylinders, crank pins on said shaft, means causing therigid connecting rod bearings to engage the crank pins during one-halfrevolution of the cylinders and to transmit two revolutions to the crankshaft during one revolution of the cylinders, a pair of stationary cammembers controlling the reciprocal movement of each piston,said cammembers adapted to lengthen the pistonstroke during the exhaust andcharging cycle and to decrease the stroke during the compressing andfiring cycle, an inlet valve and an exhaust valve in each cylinder, andan inlet and an exhaust cam formed 'onthe first named cam membersadapted to alternately open and close the inlet and exhaust valves ineach cylinder.

5. A rotary cylinder engine comprising a crank case, a pluralityofradially disposed cylinders secured to the crank case, a cylindershaft journaled to rotate carrying the crank case and cylinders, a crankshaft journaled to rotate independently of the c linder shaft andpositioned eccentrically tfiereto, a piston in each cylinder, a rigid 1engaged by vthe connecting rod bearings v, during a. portion of therevolution of the crank case and cylinders,

connecting rod on each piston, a stationary cam head at each end of thecrank case, each head having two connected circular superposed groovesformed on their inner sides, a bearing member on the inner end of eachconnecting rod, a projecting pin on each end of each bearingmemberadapted to be received by the circular grooves formed in the camheads, a plurality ofradially disposed arms onthe crank shaft betweenthe cam heads, and a pin on each arm adapted to be engaged by theconnectin rod bearing members during onehalf 0 a revolution of thecylinders.

6. A rotary cylinder engine comprising a crank case, a plurality ofradially disposed cylinders securedto the crank case, a cylinder shaftjournaled to rotate carrying the a crank shaft journaled to rotateindependently of the cylinder shaft and positioned eccentricallythereto, a piston in each cylinder, a rigid connecting rod on eachpiston, a stationary cam head at each end of the crank case, each headhaving two connected circular superposed grooves formed on their innersides, one of said circular grooves being larger in diameter than theother, a projection on each side of each connecting rod adapted tobereceivedby the grooves, a bearing member on the lower end ofeachconnecting rod, crank pins on the crank shaft adapted to becylinders, an exhaust, and an inlet ,valve in each cylinder, and a cammember in each cam head adapted to alternately open said valves onceduring each cylinders.

7. A rotary cylinder engine comprising a crank case, a plurality ofradially disposed cylinders secured to the crank case, a cylinder shaftjournaled to rotate carrying the crank case and cylinders, a crank shaftjournaled to rotate independently of the cylinder shaft and positionedeccentrically thereto, a piston in each cylinder, a rigid connecting rodon each piston, a stationary cam head at each end of the crank case,each head having -two connected circular superposed grooves formed ontheir inner sides, a bearing member on the inner end of each connectingrod, a projecting pin on each end of each bearing member adapted to bereceived by the circular grooves formed in the cam heads, a plurality ofradially disposed arms on the crank shaft between the cam heads, a pinon the outer end of each arm adapted to be engaged by the connecting rodbearing members during one-half of a revolution of the cylinder, anexhaust and an inlet valve the outer end of.

.of revolutlon of the cylinders,

revolution of theof the pistons in each cylinder, and a cam member ineach cam head adapted to alternately open said valves once during eachrevolution of the cylinders.

8. A four-cycle rotary internal combustion engine comprising a pluralityof revolving cylinders, a revolving crank shaft, means for transmittingpower to turn the crank shaft two revolutions during one revolution ofthe cylinders, a piston in each cylinder, means for transmitting tworeciprocations to each piston during one revolution of the cylinders,and means for increasing the length 0 the piston stroke during one-halfof a revolution of the cylinders and decreasing the length during theother half of revolution of the cylinders.

'9. A four-cycle rotary internal combustion engine comprising aplurality of revolving cylinders, a revolving crank shaft, means fortransmitting power to turn the crank shaft two revolutions during onerevolution of thecylinders, a piston in each cylinder, means fortransmitting two reciprocations to each piston during one revolution ofthe cylinders, means for increasing the length of thepiston strokeduring onehalf of a revolution of thecylinders and during the other halfsaid means comprising a circular cam groove regulating the stroke of thepiston during the compression and firing cycles and a connected largercircular cam groove which controls the stroke of the piston during theexhaust and charging cycle.

10. A four-cycle rotary internal combustion engine comprising aplurality of revolving cylinders, a revolving crank shaft, means fortransmitting power to turn the decreasing the length crank shaft, apiston in each cylinder, means for transmitting two reciprocations toeach piston durin one revolution of the cylinders, means or increasingthe length of the piston stroke during one-half of a revolution of thecylinders and decreasing the length during the other half of therevolution of the cylinders, said means comprising a circular cam grooveregulating the stroke of the pistons during the compression and firingcycles and a connected larger circular cam groove which controls thestroke during the exhaust and charging cycles.

lln testimony whereof l have hereunto set my hand in the presence of twosub scribing witnesses.

RICHARD B. GHATDLER, J. A. BELL. I

